From patchwork Sun Jul 3 15:06:42 2011 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [v7, 02/12] VMDK: bugfix, align offset to cluster in get_whole_cluster Date: Sun, 03 Jul 2011 05:06:42 -0000 From: Feiran Zheng X-Patchwork-Id: 103014 Message-Id: <1309705612-27079-3-git-send-email-famcool@gmail.com> To: qemu-devel@nongnu.org Cc: kwolf@redhat.com, Fam Zheng , hch@lst.de, stefanha@gmail.com In get_whole_cluster, the offset is not aligned to cluster when reading from backing_hd. When the first write to child is not at the cluster boundary, wrong address data from parent is copied to child. Signed-off-by: Fam Zheng --- block/vmdk.c | 8 +++++--- 1 files changed, 5 insertions(+), 3 deletions(-) diff --git a/block/vmdk.c b/block/vmdk.c index 3b78583..03a4619 100644 --- a/block/vmdk.c +++ b/block/vmdk.c @@ -514,21 +514,23 @@ static int get_whole_cluster(BlockDriverState *bs, /* 128 sectors * 512 bytes each = grain size 64KB */ uint8_t whole_grain[extent->cluster_sectors * 512]; - // we will be here if it's first write on non-exist grain(cluster). - // try to read from parent image, if exist + /* we will be here if it's first write on non-exist grain(cluster). + * try to read from parent image, if exist */ if (bs->backing_hd) { int ret; if (!vmdk_is_cid_valid(bs)) return -1; + /* floor offset to cluster */ + offset -= offset % (extent->cluster_sectors * 512); ret = bdrv_read(bs->backing_hd, offset >> 9, whole_grain, extent->cluster_sectors); if (ret < 0) { return -1; } - //Write grain only into the active image + /* Write grain only into the active image */ ret = bdrv_write(extent->file, cluster_offset, whole_grain, extent->cluster_sectors); if (ret < 0) {